Many examples of portable computers of this type are known in which, inevitably, it is only possible to view visual information as to the operational state of the electronic unit when the lid is in its open configuration and the display screen is visible.
European Patent Application No. EP-A-0,419,177 discloses one example of a computer of the type defined above which is battery-powered and in which various operational states of its electronic unit are provided. These states concern audio signal processing. In particular, the functions connected with recording and playback can be preset using buttons on one side of the computer which can be actuated when the lid is closed. In the recording state, the audio signals coming from a microphone are recorded in a memory by the computer after they have undergone analogue/digital conversion. Conversely, in the playback state, the signals recorded in the memory are played back by a speaker, after they have undergone digital/analogue conversion. In this example, no visual information is available as to the state of the electronic unit after the buttons have been actuated. This proves to be a particular disadvantage with respect to the functional autonomy provided by the batteries if the computer is in an operation state which has been mistakenly selected